Conventional semiconductor IC-embedded modules are known which have structures in which the semiconductor IC chip is disposed by layering in the vertical direction on a multilayered substrate (refer to Japanese Laid-open Patent Application No. 2001-102517). With these modules, thick insulating resin layers that are thicker than the bare chip are formed on both sides of the multilayer substrate, and the bare chip is thus embedded therein. Wiring layers are provided on both sides of these insulating resin layers, and the wiring layer on the surface side is used as the ground layer, whereas the wiring layer on the internal layer side is used for the power lines. Connection between semiconductor ICs is achieved through via holes and wiring layers that are formed as internal layers and surface layers of the multilayer substrate.
With the aforementioned type of conventional semiconductor IC-embedded module, a semiconductor IC chip is embedded inside an insulating resin layer formed on the surface of the multilayer substrate, and because this type of semiconductor IC is connected with a ground layer and power line provided on both sides thereof, it is possible to shorten the wiring distance for the ground layer and power lines, thereby providing a circuit device with excellent electrical characteristics.
There are various other inventions in the prior art related to the present invention (Refer to Japanese Laid-open Patent Application Nos. 2000-183540 and 2000-31207).
However, a problem with the aforementioned type of conventional semiconductor IC-embedded module is that the substrate as a whole becomes extremely thick because the substrate has a built-up configuration. Moreover, because via holes are used for connections between semiconductor ICs, a large amount of space is required for connecting the semiconductor ICs, and there are problems with increasing wiring distances. The increased wiring distances also tend to bring about impedance mismatching and noise generation. In particular, the bus lines that connect controller ICs and memory ICs operate at high clock speeds of about 100 MHz, so that unwanted high-frequency radiation is produced as the wiring distances increase, leading to problems with detrimental effects on the analog circuits of wireless systems.